this is just a cross-browser compatibility effort: neither Firefox nor NoScript really need this feature. Traditional JavaScript-based frame busting works fine in Firefox, giving it the same degree of (modest) "protection" as IE8. NoScript users, on the other hand, are already fully protected, because ClearClick is the one and only countermeasure which works against any type of Clickjacking (frame or embed based), no matter if web sites cooperate or not.

However I also said this is nice to have. I had already imagined a functionally similar declarative solution, the SUB pseudo-method of ABE rules, and HTTP-based restrictions can actually be easier to deploy in some scenarios (e.g. using a Web Application Firewall).

More important, not every IT manager will have a chance of reading the reasons I exposed so far, explaining why IE8 has no more "Clickjacking protection" than its competitors. Our typical decision maker will just read a bullet list including "Clickjacking protection", will find that no other browser dares such a claim and will base his choice (also) on that misleading comparison.

So let's add this bullet, even if it does nothing against Clickjacking that "alternative browsers" couldn't already do with traditional frame busting.